Containers having closures are well known and have a wide variety of uses. For example, they may contain medicines or pharmaceuticals. They may contain drinks, such as carbonated or non-carbonated water, colas and the like, or wines or spirits (e.g. gin or whiskey). Again they may contain petrol, oil, or household preparations or chemicals such as hair care products, detergents, bleaches and the like. The present invention is applicable to all of these areas of use and many others besides.
The conventional containers mostly have simple screw closures, which suffer from various disadvantages. For example, the closures are difficult for elderly or infirm people to operate because quite a significant torque is required and because the closure needs to be turned through more than one revolution relative to the container either to remove the closure or to replace it.
If the container is a drink container, it may be difficult for the user to seal it satisfactorily. On the one hand, the user may under-tighten the closure on the container (and thus not create an effective seal between container and closure), in which case the drink would not retain its original quality. A soft drink or still wine would not stay fresh; a carbonated beverage, sparkling wine or champagne would lose its frizziness, and spirits would evaporate. On the other hand, if the user overtightened the closure, the closure would be difficult to unscrew again.
A similar sealing problem also arises with containers for other liquids. If the user under-tightened the closure, the liquid might evaporate (e.g. gasoline), give off odorous or harmful vapors (e.g. oil or certain hazardous chemicals), or become contaminated. Again, if the user over-tightened the closure, the closure would be difficult to unscrew.
According to one aspect of the King et al., U.S. Pat. No. 5,213,225 there is provided a container neck and a container closure comprising a first thread on one of the neck and the closure, a complementary second thread on the other of the neck and the closure such that the closure is moveable from fully disengaged from the neck to fully closed by turning the closure relative to the neck by less than 360.degree., at least one stop formation carried by said one of the neck and the closure, and stop means on said other of the neck and the closure engageable with the stop formation or at least one of the stop formations to hold the closure in a closed position on the neck, the arrangement of the or each stop formation, the stop means and the threads being such that the stop means is rotated past the stop formation or at least one of the stop formations without engagement therewith when the closure is screwed on to the neck, engagement of the stop means with the stop formation or at least one of the stop formations commencing only when the closed position is neared.
However, it is perceived that even a container such as that described by King has a certain disadvantage to arthritic users in general. That is, the King patent is not child resistant. Child resistant containers are essential when dispensing analgesics or other pharmaceuticals. In this regard, while the King reference discloses a device which is easy to open, it suffers from the limitation that one must take precautionary safeguards, in order to avoid leaving this container within the grasp of children who are also similarly likely to be able to open the container.